Three dihydrochalcones derivatives 1-3, flavone 4 and phenanthrene derivative 5 were isolated, together with 9 known compofinds, from the air-dried root bark of Fissistigma bracteolatum Chatterjee. Their structures we...Three dihydrochalcones derivatives 1-3, flavone 4 and phenanthrene derivative 5 were isolated, together with 9 known compofinds, from the air-dried root bark of Fissistigma bracteolatum Chatterjee. Their structures were determined by spectroscopic （NMR, MS） and chemical methodologies.展开更多
Electronically non-adiabatic processes are essential parts of photochemical process, collisions of excited species, electron transfer processes, and quantum information processing. Various non-adiabatic dynamics metho...Electronically non-adiabatic processes are essential parts of photochemical process, collisions of excited species, electron transfer processes, and quantum information processing. Various non-adiabatic dynamics methods and their numerical implementation have been developed in the last decades. This review summarizes the most significant development of mixed quantum-classical methods and their applications which mainly include the Liouville equa- tion, Ehrenfest mean-field, trajectory surface hopping, and multiple spawning methods. The recently developed quantum trajectory mean-field method that accounts for the decoherence corrections in a parameter-free fashion is discussed in more detail.展开更多
Integrated Pest Management （IPM） technologies can reduce pest damage to crops by emphasizing non-chemical control methods thereby reducing potential negative effects of chemicals on the environment while preserving ...Integrated Pest Management （IPM） technologies can reduce pest damage to crops by emphasizing non-chemical control methods thereby reducing potential negative effects of chemicals on the environment while preserving profitability. This study investigates the adoption of eight IPM practices including intercropping, crop rotation, two improved varieties, incorporating a ＂striga chaser＂ in sorghum production, changing planting dates, altering planting density and fertilizer use. Explanatory variables include economic factors, social factors, management factors, and institutional factors. Results were consistent across logit and ordered logit analyses. Most factors affecting adoption across all crops and technologies are economic factors, including labor availability, technology resource requirements, technology complexity, and the level of expected benefits. Social factors are generally less associated with IPM technology adoption than either market or institutional factors. Results indicate that the evaluated technologies were scale-neutral and that farmer age and education level did not affect technology adoption.展开更多
文摘Three dihydrochalcones derivatives 1-3, flavone 4 and phenanthrene derivative 5 were isolated, together with 9 known compofinds, from the air-dried root bark of Fissistigma bracteolatum Chatterjee. Their structures were determined by spectroscopic （NMR, MS） and chemical methodologies.
基金supported by the National Key R&D Program of China(No.2017YFB0203405)the National Natural Science Foundation of China(No.21421003)
文摘Electronically non-adiabatic processes are essential parts of photochemical process, collisions of excited species, electron transfer processes, and quantum information processing. Various non-adiabatic dynamics methods and their numerical implementation have been developed in the last decades. This review summarizes the most significant development of mixed quantum-classical methods and their applications which mainly include the Liouville equa- tion, Ehrenfest mean-field, trajectory surface hopping, and multiple spawning methods. The recently developed quantum trajectory mean-field method that accounts for the decoherence corrections in a parameter-free fashion is discussed in more detail.
文摘Integrated Pest Management （IPM） technologies can reduce pest damage to crops by emphasizing non-chemical control methods thereby reducing potential negative effects of chemicals on the environment while preserving profitability. This study investigates the adoption of eight IPM practices including intercropping, crop rotation, two improved varieties, incorporating a ＂striga chaser＂ in sorghum production, changing planting dates, altering planting density and fertilizer use. Explanatory variables include economic factors, social factors, management factors, and institutional factors. Results were consistent across logit and ordered logit analyses. Most factors affecting adoption across all crops and technologies are economic factors, including labor availability, technology resource requirements, technology complexity, and the level of expected benefits. Social factors are generally less associated with IPM technology adoption than either market or institutional factors. Results indicate that the evaluated technologies were scale-neutral and that farmer age and education level did not affect technology adoption.
